[MPlayer-users] Encoding quality advices

[Moritz Bunkus]

Hi.

> Could this be published online somehow ? Maybe there comes other "guides" too 
> (looking at the people with great knowledge on this list) ?

I itend to wait a couple of days for replies and then to integrate that
part into my guide at http://www.bunkus.org/dvdripping4linux/ Problem
is that I should probably rewrite several parts of that guide - it's
basically over six months old, and you know how much mplayer (transcode
as well, but not as much) has changed since then, and I don't have the
time to do it properly. I'll see what I can get done this weekend.

> ( the "counting the quantesizer"-thing could improve the quality of
> full automated scripts, as I understand) .

Yes, the log file analysis can be used be tools to automatically adjust
the scaling parameters (if you'd do that you'd end up with a three-pass
encoding for the video only ;)), but it can also provide answers for
you as a human. From time to time there's a question like 'hey,
mencoder creates files that are too small! I specified this bitrate and
the resulting file is 50megs short of the target file size!'. The
reason is probably that the codec already uses the minimum quantizer
for nearly all frames so it simply does not need more bits. A quick
glance at the distribution of the quantizers can be enlightening.

Another thing is that q=2 and q=3 look really good while the 'bigger'
quantizers really lose quality. So if your distribution shows the
majority of quantizers at 4 and above then you should probably decrease
the resolution (you'll definitly see block artefacts).

-- 
 ==> Ciao, Mosu (Moritz Bunkus)